In:
Highlights of Astronomy, Cambridge University Press (CUP), Vol. 4, No. 1 ( 1977), p. 179-190
Abstract:
The USA Mariner 10 spacecraft encountered Mercury three times in 1974-1975. The 1st and 3rd encounters provided detailed observations of a well developed, detached bow shock wave which results from the interaction of the solar wind. The planet possesses a global magnetic field, and modest magnetosphere, which deflects the solar wind. The field is approximately dipolar, with orientation in the same sense as Earth, tilted 12° from the rotation axis. The magnetic moment, 5×10 22 Gauss-cm 3 , corresponds to an undistorted equatorial field intensity of 350γ, approximately 1% of Earth’s. The origin of the field, while unequivocally intrinsic to the planet, is uncertain. It may be due to remanent magnetization acquired from an extinct dynamo or a primordial magnetic field or due to a presently active dynamo. Among these possibilities, the latter appears more plausible at present. In any case, the existence of the magnetic field provides very strong evidence of a mature, differentiated planetary interior with a large core, R c ≈ 0.7R M , and a record of the history of planetary formation in the magnetization of the crustal rocks.
Type of Medium:
Online Resource
ISSN:
1539-2996
DOI:
10.1017/S1539299600002562
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
1977
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